MERRF syndrome

MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. It is extremely rare, and has varying degrees of expressivity owing to heteroplasmy. [Source: Wikipedia ]

Synonyms
Myoclonic epilepsy and ragged red fibers
OrphaNet reference
MERRF syndrome 
May Cause
Dysmyelinating disease
Mitochondrial disorder
Mitochondrial encephalopathy
Mitochondrial myopathy